Means for energizing antenne



March 21, 1933- N, E, LINDENBLAD 1,902,086

MEANS FOR ENERGIZING ANTENNZE Filed May 22, 1929 30 58 1 you INVENTOR NlLS E; UNDENBLAD 7 ,LU'U'M/ ATTORNEY Patented Mar. 21, 1933 UNITED sTA'rEs PATENT", OFFICE.

NILS EL LINDENBLAD, OF PORT JEFFERSON, -NEW YORK, ASSIG-NOR TO RADIO CORPO- RATION OF AMERICA, A CORPORATION OF DELAWARE MEANS FOR EN RGIZING ANTENNZE Application filed May 22,

This invention relatesto feeders or lead-in structures for antennae and has for one of 1ts ob ects the provlsion of new and useful meth ods and means for energizing antennae.

* number of half wave lengths long radiation in four directions may be obtained; by the staggering of the arrangement-referred to I have shown how radiation is made predominantly bidirectional; and, by the use of staggered pairs of the bidirectional arrangement, I have shown how unidirectional radiation may be obtained. Those st'r'uctureshave, for supplying energy thereto, feeders which have certain portions run relatively close together i and parallel, and other portions which diverge in order to supply energy'to the Y closed 111 my copending application referred radiators.

I have found that where the antenna reed ers or lead-ins were run close together and substantially parallel, because of the substan- -tially concentric fields about the leads there is radiation cancellation and hence those portions do not affect the radiational directivity of the antenna. On the other hand where the feeders diverge the fields thereabout are no longer concentric, they no longer cancel but tend to set up large radiation components which militate against accurate directional radiation. Accordingly another and more specific object of this invention is to provide a method and means whereby radiation from the diverging portions of feeders or lead-in structures is substantially eliminated or lessened to such a degree that it has no appreciable militating effect.

Still another object of this invention is to provide an additional arrangement of supply feeders for antennae, of the character referred to, in which diverging portions are dispensed j with.

pending application referred to'above, it is Inot limited use thereto, but, the principals 1929. Serial No. 365,024.

of my invention may be applied to any radiating system. o The invention may most readily be understood by referring to the accompanying drawing in which 7 Figure 1 illustrates a manner in which radiation cancellation from the diverging portions of feeders is obtained by providing additional lead-in structure;

liigure 2 is an embodiment wherein radiation is reduced from the diverging portions of %he feeder structure by looping the same; anc

Figure 3 shows a manner in which diverging feeders may be dispensed with.

Referring to Figure 1 numeral 1 indicates a transmitter supplying, over the relatively close parallel portions 3, 5 of feeders and diverging portions 7 9, energy to radiators 11, 13. 'Radiators 11, 13 are excited, as distohereinbefore,in phase opposition; hence, because of the-close contiguity of portions 3, 5 and because of the substantial concentricity of the fields thereabout, there will be substantially no radiation therefrom. V

' However, there is no radiation cancellationof portion 7 by portion 9 or the reverse because those portions do not have substantially concentric fields. In order, therefore, to cancel radiation from those portions I run additional leadsor feeders from point'15 to point 17 substantially parallel to and close to portion 7 and a lead parallel to portion 9 from point 19 on lead 5 to point 21.

It will, therefore, be clear that because of the free electrical ends 17 and 21, standing waves will beproduced on the leads or wires 17,15 and 19, "21. By suitably choosing the lengthsof these wires the standing waves on them may be made to exist in phase opposi- In this manner, as portions 7 and 9 will have u substantially concentric and opposing fields thereabout radiation from diverging portions 7 and 9 will'be practically eliminated. f

Of course, it may beimpossible to have points '17 and 21, in order tohave phaseopposition with the diverging portions of the feeders or lead-ins, exactly opposite the extreme ends of portions 7 and 9. However, it will be found that points 17 and 21 will be sufiiciently opposite to the extreme ends of the diverging portions of the antenna feeders so that sufficient radiation cancellation is obtained.

In Figure 2 reduction of radiation along the diverging portions 7 0, 90 is obtained by placing loops in, or folding up the diverging portions. The loops 7 2 may or may not be in the same plane.

The reason why radiation from the diverging portions in this case is reduced, may be explained as follows. If the diverging portions were straight, the standing waves thereon caused by reflection from points 25 and 23 would have points of average maximum potential relatively far apart. Accordingly, the paths that electrostatic flux would take in travelling between these points would be large and radiation would be sufiiciently great to lessen the desired directive characteristics of the antenna. By folding up the diverging portions, the distances between points of' average maximum potential is reduced, and accordingly, the lengths of the paths of electrostatic flux are reduced resulting in greatly decreased radiation from the diverging portions 70, 90. This looping is to be considered, therefore, as lessening the radiation resistance of the portions 70, 90.

In Figure 3 I have shown a manner in which diverging portions for energizing antennae of the general character described are eliminated. For the sake of example, I have.

indicated four staggered radiators 30, 40, 50, 60. For radiation in the direction of the arrow the standing waves on these wires, as disclosed in my copending application, should have phase relationships so that considering the standing wave on radiator 40 as a reference point, the wave on 30 should be 90 degrees therefrom, the wave 50 should be 270 degrees therefrom and the wave on 60 should be 180 degrees therefrom.

By the use of parallel paths or feeders such as 32, 34; 42, 44; 52, 54; 62, 64, connected between transmitter 1 and radiators 30, 40, 50, 60, standing waves may be produced on the radiators. The paths should be connected to the radiators intermediate their ends and, the portions included between, say, points 36, 38, should be equal to the characteristic impedance of, for example, the lead-ins 32, 34. And similarly, for example, the impedance between points 66, 68, should be equal to the characteristic impedancev of lines 62, 64.

Because of the close propinquity and parallel paths of the lead-ins, or feeders, for example, 32, 34, radiation therefrom is substantially eliminated.

Having thus described my invention, what I claim is:

1. In combination, a pair of radiators, a pair of diverging feeders for supplying energy thereto, and leads run from each feeder close to and parallel to the other feeder.

2. In combination a pair of radiators, a pair of diverging feeders for supplying energy thereto and leads having free electrical ends run from each feeder close to and parallel to the other feeder.

3. In an antenna comprising radiators having diverging feeders for supplying energy thereto, a lead connected to one feeder running pa-ralleland contiguous to another feeder for cancellation of radiation therefrom.

4. Inan antenna comprising a pair of linear radiators excited in phase opposition having diverging feeders for supplying energy thereto, leads, cross connected to the energy supply feeders running parallel and in close proximity to the radiator supply feeders, said parallel run leads having free electrical ends...

5. An antenna having a plurality of radiators, diverging feeders therefor, and a lead, from each feeder taken at a point where the feeders begin to diverge to feed the indi: vidual radiators of the antenna, running parallel and close to a feeder other than the one to which it is connected.

6. In an antenna comprising a pair of radiators having diverging feeders for supplying energy thereto, a lead connected to one feeder running parallel and close to the other feeder for cancellation of radiation therefrom.

NILS E. LINDENBLAD. 

